ASTM A748/A748M-87(2012)

Standard Specification for Statically Cast Chilled White Iron-Gray Iron Dual Metal Rolls for Pressure Vessel Use

ABSTRACT
This specification covers statically cast dual metal rolls with the outer layer of the roll body being chilled white iron of different chemical composition than the core and journals of the roll which is gray cast iron. The castings are suitable for pressure containing parts such as pressure vessels, the design strength of which is based on the gray iron portion of the cylinder, and for service at the specified temperatures. The melting procedure shall be optional with the foundry and the casting process shall be controlled to produce a metallurgical bond between the chilled white iron exterior and gray iron interior. The chilled white iron exterior shall be made to the specified minimum hardness and the gray iron portion of the roll shall conform to the applicable class as determined by design requirements. The roll shall conform to the tensile strength requirement to be determined by tensile test and shall meet the required thickness. All surfaces shall be machined or ground, or both, prior to the rolls being placed into service.
SCOPE
1.1 This specification covers statically cast dual metal rolls with the outer layer of the roll body being chilled white iron of different chemical composition than the core and journals of the roll which is gray cast iron. The castings are suitable for pressure containing parts, the design strength of which is based on the gray iron portion of the cylinder. The castings are suitable for service at temperatures up to 450°F [232°C].  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.3 The following safety hazards statement pertains only to the test method portion, 9, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Sep-2012
• ICS: 77.140.80 - Iron and steel castings
• Technical Committee: A04 - Iron Castings
• Drafting Committee: A04.01 - Grey and White Iron Castings

Relations

• Replaces: ASTM A748/A748M-87(2008) - Standard Specification for Statically Cast Chilled White Iron-Gray Iron Dual Metal Rolls for Pressure Vessel Use
• Effective Date: 01-Oct-2012

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:A748/A748M −87 (Reapproved 2012)
Standard Specification for
Statically Cast Chilled White Iron-Gray Iron Dual Metal Rolls
for Pressure Vessel Use
This standard is issued under the fixed designationA748/A748M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 ASTM designation and year of issue,
3.1.2 Dimensions of dual rolls,
1.1 This specification covers statically cast dual metal rolls
3.1.3 Class of gray iron in the roll core (see 4.2),
with the outer layer of the roll body being chilled white iron of
3.1.4 Inspection requirements, if different (see 10.1),
different chemical composition than the core and journals of
3.1.5 Certification, if required (see 11.1), and
the roll which is gray cast iron. The castings are suitable for
3.1.6 Special position of marking information, if required
pressure containing parts, the design strength of which is based
(see 12.1).
on the gray iron portion of the cylinder. The castings are
suitable for service at temperatures up to 450°F [232°C]. 3.2 Any additional requirements not covered in this speci-
fication are subject to agreement between the manufacturer and
1.2 The values stated in either SI units or inch-pound units
purchaser.
are to be regarded separately as standard. The values stated in
each system may not be exact equivalents; therefore, each
4. Materials and Manufacture
system shall be used independently of the other. Combining
4.1 The melting procedure shall be optional with the
values from the two systems may result in non-conformance
foundry.
with the standard.
4.2 The chilled white iron exterior of the roll body shall be
1.3 The following safety hazards statement pertains only to
made to a minimum hardness of 60 Scleroscope “C”. The gray
the test method portion, 9, of this specification: This standard
iron portion of the roll shall conform to the applicable class of
does not purport to address all of the safety concerns, if any,
Specification A278/A278M, as determined by design require-
associatedwithitsuse.Itistheresponsibilityoftheuserofthis
ments.ThescopeofthisspecificationshallincludeNos.20,25,
standard to establish appropriate safety and health practices
30, 35, 150, 175, 200, and 250 of Specification A278/A278M.
and determine the applicability of regulatory limitations prior
to use.
4.3 The casting process shall be controlled to produce a
metallurgical bond between the chilled white iron exterior and
2. Referenced Documents
gray iron interior of the roll body.
2.1 ASTM Standards:
A278/A278M Specification for Gray Iron Castings for
5. Test Requirements
Pressure-Containing Parts for Temperatures Up to 650°F
5.1 Tensile Requirements—Tensile bars removed from a
(350°C)
prolongation at one end of the roll journal, in accordance with
A667/A667M Specification for Centrifugally Cast Dual
Specification A278/A278M, shall have a tensile strength not
Metal (Gray and White Cast Iron) Cylinders
less than 80 % of that specified by the applicable class of
Specification A278/A278M.
3. Ordering Information
5.2 Thickness of Chilled White Iron:
3.1 Orders for material under this specification shall include
5.2.1 The thickness of the clear chilled white iron plus the
the following information:
mottled iron at the roll face shall not be more than 30 % of the
total finished wall thickness.
This specification is under the jurisdiction of ASTM Committee A04 on Iron
Castingsand is the direct responsibility of Subcommittee A04.01 on Grey andWhite
5.2.2 The thickness of the chilled white iron exterior of the
Iron Castings.
roll body shall be determined by measuring the chill depth at
Current edition approved Oct. 1, 2012. Published November 2012. Originally
the ends of the roll face.
approved in 1977. Last previous edition approved in 2008 as A748/A748M – 87
(2008). DOI: 10.1520/A0748_A0748M-87R12.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6. Fi
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